It is known that acceleration/deceleration of a following vehicle is controlled by concurrently using PID control by a feedback control system based on an inter-vehicle distance difference with a preceding vehicle and control by a feed-forward system according to the acceleration/deceleration adjusting status of the preceding vehicle based on acceleration/deceleration adjusting information obtained via inter-vehicle communication (see Patent Document 1, for example). The acceleration/deceleration adjusting information is accelerator pedal operation information (accelerator position) and brake operation information (brake position). The acceleration/deceleration of the following vehicle is controlled by adding a feed-forward control amount, which corresponds to the accelerator position and the brake position of the preceding vehicle, to a feed-back control amount determined based on the inter-vehicle distance difference.
[Patent Document 1] Japanese Laid-open Patent Publication No. 11-013507